In the last few decades, the semiconductor industry has been able to maintain steady improvements of device performance by the scaling of silicon-based devices. However, it is believed this approach will soon meet both scientific and technical limits, and there have been tremendous efforts to seek alternative device technologies. One such alternative is the use of graphene in semiconductor structures.
Graphene is a layer of carbon atoms bonded in a honeycomb crystal lattice. Graphene has a high carrier mobility, as well as low noise, allowing it to be used as a substitute for silicon in the channel in a FET. Intrinsic graphene is a semi-metal or zero-gap semiconductor, with an E-k relation that is linear at low energies near the six corners of the two-dimensional hexagonal Brillouin zone, leading to zero effective mass for electrons and holes. Graphene has high electron mobility at room temperature, with reported values of 15,000 cm2V−1s−1. Moreover, graphene resistivity is very low, e.g., less than the resistivity of silver, which is the lowest resistivity substance currently known at room temperature. Measurements have shown that graphene has a breaking strength 200 times greater than steel, with a tensile strength of 130 GPa. Additionally, graphene has thermal properties comparable to diamond for basal plane thermal conductivity. As for optical properties, graphene can be saturated readily under strong excitation over the visible to near-infrared region, due to the universal optical absorption and zero band gap, which permits application in ultrafast photonics.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.